Adding a powered sub...battery wire question

I am adding a powered sub to a new system I installed in my '95 Mercedes SL320. The existing system included a bose sub behind the front seat. As getting the battery wire to the battery in the trunk requires a lot of interior trim removal, I was wondering if I can pickup power from the multi pin connector from the bose sub no longer being used? The connector uses a female spade connection and I have confirmed I have the voltage at the pin, so I was thinking of adding a male spade connector to my battery wire from the amp and plug into the old amps connector??